Diabetes mellitus is a serious and chronic metabolic disease that is characterized by high blood glucose (hyperglycemia) and affects millions of people worldwide. SGLT2 is a Sodium-dependent Glucose co-Transporter protein, which affects the reabsorption of glucose in the kidney. It is estimated that 90% of renal glucose reabsorption is facilitated by SGLT2. Since glucose reabsorption is mediated predominantly by SGLT2 and because high glucose levels have been identified as a cause of disease in diabetes, SGLT2 has become a drug target for type 2 diabetes therapy. Selective inhibition of SGLT2 has the potential to reduce hyperglycemia by inhibiting glucose reabsorption in the kidney with elimination of glucose by excretion in the urine (glucosuria).
Sodium-glucose co-transporter 2 (SGLT2) inhibitors are a new class of diabetic medications indicated only for the treatment of type 2 diabetes. In conjunction with exercise and a healthy diet, they can improve glycemic control. They have been studied alone and with other medications including metformin, sulfonylureas, pioglitazone, DPP-4 inhibitors and insulin.
Drugs in the SGLT2 inhibitors class include, but are not limited to canagliflozin, dapagliflozin, empagliflozin and the like. The structures of these SGLT2 inhibitors are represented below:

SGLT2 inhibitor compounds and their preparation process have been described in the art, for example U.S. Pat. No. 7,943,788 disclosed canagliflozin; U.S. Pat. No. 6,515,117 disclosed dapagliflozin and U.S. Pat. No. 7,579,449 disclosed empagliflozin.
Solid forms of SGLT2 inhibitor compounds in the form of crystalline forms, solvates, co-crystals, eutectic mixtures etc. have been described in the art on various occasions, e.g. U.S. Pat. Nos. 6,774,112, 7,723,309, 7,919,598, 7,943,582, 9,006,188, 9,035,044, WO 2002083066, WO2004063209, WO2007114475, WO2008002824, WO2013064909, WO2012163546, WO2013079501, WO2014178040, WO2015071761, WO2015132803, WO2015198227, WO2016018024, US2015307540, IN1985/MUM/2013, CN102167715B and CN103965267A.
Further, amorphous form of dapagliflozin has been described in the art, for example in U.S. Pat. No. 8,999,941; PCT Publication Nos. WO 2015/104658, WO 2015/132803 and WO 2015/040571.
Obtaining suitable solid forms of a drug is a necessary stage for many orally available drugs. Suitable solid forms possess the desired properties of a particular drug. Such suitable forms often possess more favorable pharmaceutical and pharmacological properties or may be easier to process than known forms of the drug itself or may be used as a drug product intermediate during the preparation of the drug. For example, new drug formulations comprising crystalline forms of a given drug may have superior properties, such as solubility, dissolution, hygroscopicity and storage stability over existing formulations of the drug.
Discovering new polymorphic forms, solvates or co-crystals of a pharmaceutical product can provide materials having desirable processing properties, such as ease of handling, ease of processing, storage stability, and ease of purification or as desirable intermediate forms that facilitate conversion to other solid-state forms. New polymorphic forms, solvates or co-crystals of a pharmaceutically useful compound can also provide an opportunity to improve the performance characteristics of a pharmaceutical product. It enlarges the repertoire of materials that a formulation scientist has available for formulation optimization, for example by providing a product with different properties, e.g., better processing or handling characteristics, better purity, improved dissolution profile, or improved shelf-life.
A co-crystal of a drug is a distinct chemical composition between the drug and the co-crystal former, and generally possesses distinct crystallographic and spectroscopic properties when compared to those of the drug and the co-crystal former individually. Unlike salts, which possess a neutral net charge, but which are comprised of charge-balanced components, co-crystals are comprised of neutral species. Thus, unlike a salt, one cannot determine the stoichiometry of a co-crystal former based on charge balance. Indeed, one can often obtain co-crystals having stoichiometric ratios of drug to the co-crystal former of greater than or less than 1:1. The stoichiometric ratio of an API to co-crystal former is a generally unpredictable feature of a co-crystal.
In view of the foregoing, it would be desirable to provide new solid forms of SGLT2 inhibitors. Further, it would be desirable to have reliable processes for producing these solid forms. Therefore, the present invention addresses the need in the art for pharmaceutically useful solid forms of SGLT2 inhibitor that may have improved physicochemical properties, such as a higher solubility and dissolution rate, enhanced flow properties and enhanced stability.
Although processes have been described in the art for the preparation of amorphous dapagliflozin, there still remains a need for simple, environmental-friendly, stable, economical and industrially feasible and scalable processes for the preparation of dapagliflozin amorphous form.